Marcus,
Thanks for the constructive questions...
>Does anyone have pictures or other documentation showing a particular
>racer using aluminum cranks in the mountains, and steel cranks on the
>flats?
Yes. When we wrote the article in question for
BQ, I worked with Aldo Ross, who found in his
collection of contemporary magazines a number of
photos of racers - mostly French - that used
cotterless aluminum cranks in the mountains and
cottered steel cranks on the flats.
>In the same season?
Yes.
>In the same race?
I think so, but I'd have to check with Aldo.
>Was this common or the exception?
The photo in BQ Volume 4, No. 3, p. 16 shows both
Louison Bobet and Lucien Lazaridès with aluminum
cranks, but Hugo Koblet on cottered cranks. 17th
stage of the 1951 Tour, from Montpellier to
Avignon via Mt. Ventoux - so it was mountainous.
This indicates that several racer at least used
aluminum cranks, but others stuck with cottered
steel cranks - including that year's winner.
>Did these racers switch cranks or switch bikes?
That I don't know. However, from what I read,
they appear to have used the same bike for the
entire race. One report says that the mechanics
complained about the workload of switching the
gearing on almost every bike almost every night.
(Back then, the Tour was for national teams, and
for most of them, the Tour's organizers provided
the mechanics.)
>Did they have other specialized equipment for the mountains or the flats?
The literature said that Hugo Koblet switched
gearing a lot, but not bikes. See the article in
BQ Vol. 2, No. 2 that describes Koblet's bike in
detail (taken from the contemporary press, with
Daniel Rebour drawings.)
>Is there just some quotidian explanation? For example: "the next day, the
>bike with the aluminum cranks had a flat, so I grabbed the backup bike
>with the steel cranks." Or, "early in the season we rode the bikes with
>the steel cranks, but then Guiseppe worked a deal with someone, and we got
>some of the new, cool aluminum cranks."
It seems to be pretty consistent, so I doubt the explanation is just coincidence. In many cases, both the steel and aluminum cranks were made by the same company, Stronglight.
Jan Heine
Editor
Bicycle Quarterly
140 Lakeside Ave #C
Seattle WA 98122
http://www.bikequarterly.com